Vehicle generators primarily addressed by this invention are typically fashioned as claw pole inductor-alternator machines. The current induced during the rotor rotation in the rotor winding is typically conducted to two cylindrical slip rings mounted at the end of the rotor shaft and connected with the rotor winding. From there, the current is fed via so-called “brushes” to a rectifier and regulator arrangement. Such a normal generator construction is described in diverse publications such as, for example, in DE 10113673 A1, DE 4430073 A1, EP 1311051 A2, EP 671802 A1, US 2005/0127777 A1, EP 1337013 A2 and U.S. Pat. No. 7,417,353 B2. With reference to the transmission of the current induced in the rotor winding to the stator, alternatives have already been suggested, yet without commercial success, such as, for example, in GB 1138526 a transmission by means of a “slip ring arrangement” with planar brush running surfaces with a first central contact zone and a second contact zone surrounding it in a circular form. In DE 2926294 A, the transmission is accomplished by means of two rotor slip rings with planar contact faces that are arranged on both sides of a carrier; they each abut a brush axially. For the current transmission between rotor and stator of an electrical machine, a slip ring arrangement was suggested where a rotor slip ring permanently contacts an axially opposite stator slip ring (DE 973236). An axial slip ring arrangement for current transmission in dynamo-electric machines is also described in U.S. Pat. No. 2,623,188.
Slip ring arrangements as such are otherwise known not only for the transmission of current induced in the rotor windings to the generator stator but also in connection with signal transmission. Such a slip ring arrangement serving signal transmission is, for example, found in U.S. Pat. No. 4,275,376.
Slip ring arrangements for the transmission of electrical signals and/or power are also the subject of DE 20 2010 002327. For a slip ring arrangement consisting of two pairs of slip rings, an alternating sequence of rotor and stator slip rings is suggested, i.e., the sequence of first rotor slip ring, first stator slip ring, second rotor slip ring, second stator slip ring together with the corresponding support structure. The stack of four slip rings is arranged and secured between a rotor collar and a shaft nut screwed on the rotor.
It is suggested for a slip ring arrangement consisting of at least three pairs of slip rings that two opposing slip rings each be arranged at adjacent rotor slip ring supports and stator slip ring supports. This results in the sequence first stator slip ring, first and second rotor slip ring, second and third stator slip ring, third rotor slip ring.
Despite diverse attempts of optimizing dynamo-electric machines of the initially described type in relation to the connection of the current-carrying rotor winding to the stator, there is still a demand for a practical, commercially realizable solution that offers a long-lasting, reliable, cost effective and compact dynamo-electric machine of the above mentioned type.